The present invention relates to diaphragm segmentation in a chest X-ray radiograph, and more particularly, to estimating regions representing the diaphragm in a chest X-ray radiograph, for nodule detection in the diaphragm region.
Nodules are small masses of tissue, which can form on various organs in the human body, such as the lungs. Lung nodule detection can be used for advance cancer screening. Accordingly, computer implemented methods for automatic nodule detection methods have been developed to detect nodules in chest X-ray radiographs. Such automatic nodule detection methods determine locations in a chest X-ray radiograph at which there is a high probability that a nodule exists.
In chest X-ray radiographs, diaphragm regions typically exhibit unique intensity characteristics. Diaphragm regions can represent special regions of interest for nodule detection in chest X-ray radiographs. For example, in lung nodule detection, detectable nodules in diaphragm regions are typically much larger and less prominent in intensity distribution, thereby exhibiting very different image characteristics from nodules in the upper lung lobes. Accordingly, special handling may be required to ensure reliable detection of nodules in diaphragm. In order to initiate special handling of the nodules in diaphragm regions, a valid segmentation of the diaphragm is need. However, even though many techniques have been developed for segmentation of lung lobes, heart regions, and ribs in chest x-ray radiographs, diaphragm segmentation has not been well addressed. Furthermore, diaphragm regions typically do not have a clear-cut definition in chest x-ray images, and there is not much edge information and/or intensity information that provides sufficient support segmenting diaphragm regions using a general segmentation algorithm. Therefore, a method of diaphragm segmentation in chest X-ray radiographs is desirable.